Tuesday, July 13. 2010

A small change to the theory of gravity implies that our universe inherited its arrow of time from the black hole in which it was born.

"Accordingly, our own Universe may be the interior of a black hole existing in another universe." So concludes Nikodem Poplawski at Indiana University in a remarkable paper about the nature of space and the origin of time.

The idea that new universes can be created inside black holes and that our own may have originated in this way has been the raw fodder of science fiction for many years. But a proper scientific derivation of the notion has never emerged.

Today Poplawski provides such a derivation. He says the idea that black holes are the cosmic mothers of new universes is a natural consequence of a simple new assumption about the nature of spacetime.

Poplawski points out that the standard derivation of general relativity takes no account of the intrinsic momentum of spin half particles. However there is another version of the theory, called the Einstein-Cartan-Kibble-Sciama theory of gravity, which does.

This predicts that particles with half integer spin should interact, generating a tiny repulsive force called torsion. In ordinary circumstances, torsion is too small to have any effect. But when densities become much higher than those in nuclear matter, it becomes significant. In particular, says Poplawski, torsion prevents the formation of singularities inside a black hole.

That's interesting for a number of reasons. First, it has important implications for the way the Universe must have grown when it was close to its minimum size.

Astrophysicists have long known that our universe is so big that it could not have reached its current size given the rate of expansion we see now. Instead, they believe it grew by many orders of magnitude in a fraction of a second after the Big Bang, a process known as inflation.

The problem with inflation is that it needs an additional theory to explain why it occurs and that's ugly. Poplawski's approach immediately solves this problem. He says that torsion caused this rapid inflation.

That means the universe as we see it today can be explained by a single theory of gravity without any additional assumptions about inflation.

Another important by-product of Poplawski's approach is that it makes it possible for universes to be born inside the event horizons of certain kinds of black hole. Here, torsion prevents the formation of a singularity but allows a HUGE energy density to build up, which leads to the creation of particles on a massive scale via pair production followed by the expansion of the new universe.

This is a Big Bang type event. "Such an expansion is not visible for observers outside the black hole, for whom the horizon's formation and all subsequent processes occur after infinite time," says Poplawski.

For this reason, the new universe is a separate branch of space time and evolves accordingly.

Incidentally, this approach also suggests a solution to another of the great problems of cosmology: why time seems to flow in one direction but not in the other, even though the laws of physics are time symmetric.

Poplawski says the origin of the arrow of time comes from the asymmetry of the flow of matter into the black hole from the mother universe. "The arrow of cosmic time of a universe inside a black hole would then be fixed by the time-asymmetric collapse of matter through the event horizon," he says.

In other words, our universe inherited its arrow of time from its mother.

He says that daughter universes may inherit other properties from their mothers, implying that it may be possible to detect these properties, providing an experimental proof of his idea.

Theories of everything don't get much more ambitious than this. Entertaining stuff!

Comments

"Accordingly, our own Universe may be the interior of a black hole existing in another universe." So concludes Nikodem Poplawski at Indiana University in a remarkable paper about the nature of space and the origin of time."

Wow. The only thing remarkable about Nikodem Poplawski's paper is that such pseudoscientific hogwash can originate from an institution of higher learning in this day and age. I say, shame on the University of Indiana. The very idea of a black hole is based on the concept of continuity, an idea that is not only illogical (it leads to an infinite regress), but is not even scientific in the Popperian sense of falsification. Even Einstein, Mr. Continuity himself, had doubts about continuity.

Worst of all is the idea that somehow time has a direction of flow, i.e., an arrow. The idea that we are moving in time in one direction or another is a conceptual disaster. Why? Because time cannot change by definition. This is the reason that Karl Popper called spacetime "Einstein's block universe in which nothing happens" (source: Conjectures and Refutations). Absolutely nothing can move in spacetime for this reason. Why isn't Poplawski aware of this fact and how did his Star-Trek voodoo physics paper pass peer review? This is truly a sad commentary on the state of modern physics. This stuff is not even wrong.

The problem with the physics community is that theirs is an incestuous science that has been spawning hideous monstrosities for some time now. Their bunker mentality (the public is stupid and is the enemy) prevents them from considering other points of view, especially views that contradict their worldview. They have completely abandoned the search for a foundational understanding of nature and they insist on building up on their erroneous assumptions. Physicists do not even understand motion and yet they feel confident enough to create all sorts of silliness like wormholes, multiple universes and time travel. How dare they think that they are qualified to teach us about the origin of the universe when they are wallowing in ignorance about the most basic aspects of the universe?

Ask a physicist to explain why two bodies in relative inertial motion remain in motion and you'll come face to face with abject ignorance. Vast and profound ignorance is the norm in the physics community.

Let me add that I am deeply disappointed that publications like TR are still printing such pseudoscientific fairy tales under the banner of legitimate science. Paul Feyrabend was right when he wrote in Against Method, "[...]the most stupid procedures and the most laughable results in their domain are surrounded with an aura of excellence. It is time to cut them down in size, and to give them a more modest position in society." He might as well have been writing about physicists like Nikodem Poplawski.

Tuesday, May 11. 2010

It seems that time travel has captured the imaginations of people since time began. Einstein’s Special Theory of Relativity speculated that traveling close to the speed of light would physically alter time by dilating it. This means that there should be places where time slows down, and others where time speeds up. Discovery News reports that Hawking recently expanded on this theory, outlining several theoretically realistic ideas for traveling through time.

Hawking almost perfectly explains his theories in a letter to the Daily Mail in a way that non-cosmologists can understand. He encourages people to think of time as dimension just like width, height and length. Just as when you travel in a car, you can go forward, right or left. The fourth dimension would be time. And all around us are wormholes that could act as a time tunnel.

As Hawking writes, "Down at the smallest of scales, smaller even than molecules, smaller than atoms, we get to a place called the quantum foam. This is where wormholes exist. Tiny tunnels or shortcuts through space and time constantly form, disappear, and reform within this quantum world. And they actually link two separate places and two different times." The time tunnels are too small for people to travel through, but Hawking and others believe that someday a wormhole could be widened for person or ship to travel through to the future.

Hawking points out that travel backward in time may be impossible due to the cause and effect theory. (For example, if you travel backward and prevent your birth, how could you have ever been born?) Further, Hawking suspects that radiation might collapse the wormholes, rendering them useless anyway.

Another way to time travel rides on the “time as a river” theory. As Einstein proposed before him, there are places where time moves faster and where time moves slower. It depends if there are things that drag on space, much like rocks in a moving river. The Earth itself drags on space, meaning time moves slower on Earth than it does in space. Hawking points out that the Global Positioning System satellite network in space must be adjusted because of this.

Further, Hawking claims black holes may be the key to time travel. He asks us to imagine a spaceship orbiting a super-massive black hole some 26,000 miles away. To us, it would just look like the ship makes one orbit every 16 minutes. As Hawking writes, "A black hole ... has a dramatic effect on time, slowing it down far more than anything else in the galaxy. That makes it a natural time machine. … But for the brave people on board, close to this massive object, time would be slowed down. For every 16-minute orbit, they'd only experience eight minutes of time."

Hawking reminds us that nothing can travel faster than the speed of light, and that time will always slow down right before reaching this speed. Therefore, if we had a ship that could travel near the speed of light, we could also travel in time.

Katherine Butler is a TV writer who writes for the Mother Nature Network.

Personal comment:

Some ideas we've already heard or read about I feel, about time as an "architecturable" dimension. But a good short reminder by S. Hawking concerning actual scientific knowledge of time (travel).

Metamaterials allow the creation of adjacent spaces with their own laws of physics, just like the multiverse.

Metamaterials are substances in which physicists have fiddled with a material's ability to support electric and magnetic fields. They can be designed to steer electromagnetic waves around, over and behind objects to create invisibility cloaks that hide objects.

If that sounds a little like the way gravitational fields can bend light, then you won't be surprised to learn that there is a formal mathematical analogy between optical metamaterials and general relativity.

The idea that anything Einstein can do, metamaterials can do too has fueled an explosion of interest in "electromagnetic space". Physicists have already investigated black holes that suck light in but won't let it out and wormholes that connect different regions of electromagnetic space.

Today, Igor Smolyaninov at the University of Maryland in College Park says that the analogy with spacetime can be taken much further. He says it is possible to create metamaterials that are analogous to various kinds of spaces dreamt up by cosmologists to explain aspects of the Universe.

In these theories, space can have different numbers of dimensions that become compactified early in the Universe's history, leaving the three dimensions of space and one of time (3+1) that we see today. In symmetries of these spaces depend on the dimensions and the way they are compactified and this in turn determines the laws of physics in these regions.

It turns out, says Smolyaninov, that it is possible to create metamaterials with electromagnetic spaces in which some dimensions are compactified. He says it is even possible to create substances in which the spaces vary from region to region, so a space with 2 ordinary and 2 compactified dimensions, could be adjacent to a space with just 2 ordinary dimensions and also connected to a 2d space with 1 compactified dimension and so on.

The wormholes that make transitions between these regions would be especially interesting. It ought to be possible to observe the birth of photons in these regions and there is even a sense in which the transition could represent the birth of a new universe."A similar topological transition may have given birth to our own Universe," says Smolyaninov.

He goes on to show that these materials can be used to create a multiverse in which different universes have different properties. In fact it ought to be possible create universes in which different laws of physics arise.

That opens up a new area for optical devices. Smolyaninov gives the example of electromagnetic universes in which photons behave as if they are massive, massless or charged depending on the topology of space and the laws of physics this gives rise to.

Just what kind of devices could exploit this behaviour isn't clear yet. If you think of any, post them here. This is clearly a field that for the moment appears to be limited only by the mind of the designer.

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